I have decided to create this fresh thread so that all those involved in the discussion that I instigated over R1 V R2 and the ins and outs of NTSC and PAL can read the objective academic evidence that I did not include in my subjective postings. The following information was transcribed by me during a phone conversation with SALFORD UNIVERSITY Lecturer John Bingham. " We should start with the basics. Both 60hz aka NTSC and 50hz aka PAL in the Region 1 and Region 2 DVD format have the exact same horizontal resolution. 720 PIXELS across the screen This is HORIZONTAL resolution and is the same for both standards. While 50hz/PAL has 576 active lines as VERTICAL resolution While 60hz/NTSC has 480 active lines as VERTICAL resolution. To fit into an standard definition DVD capacity, memory is assigned in chips in terms of a power of 2. The basic unit is 1 MEGABIT. That is not a million but 2 to the power of 20. 1048576 Memory locations that being 1 Megabit of memory. When decoding one seeks to fit a complete video frame into a simple multiple of the above number. What is normally used is 4 MEGABITS. 4194304 Memory locations This is the basic video frame within the DVD format. Now, totally uncompressed video, which gives you 8 Bits for each of the RGB colours is normally stored in what is called 4:4:4 format This is pure uncompressed component video Y,Cr,Cb or sometimes known as YUV format. Our eyes are very sensitive to brightness/luminance details but not as senstive to colour detail. So the normal broadcast quality standard is to work at 4:2:2 format This means that half the fine detail in the colour has been lost as the viewer is less conscious of this lost colour detail. But this is still not enough data reduction to allow a small amount of memory to be used in domestic/consumer applications. So for 60hz/480line DVD aka NTSC the colour detail is reduced by a further factor of 2 to give... 4:1:1 format This means that there is 1Bit of red difference and 1Bit of blue difference, component information for every 4 bits of luminance information. At 8 Bit (luminance) video depth this means a complete video frame of 480 x 720 Pixels. 4147200 Memory locations this is just below 4 Megabits. One 4 megabit block of memory can hold one complete frame. This is NOT POSSIBLE with 50hz / 576 line PAL !!!!! As a single frame would then require... 4976640 Memory locations. So to reduce the information back to just below 4 Megabits per frame for a PAL/ REGION 2 DVD the colour detail information is again reduced by half to give what is known as 4:1:0 format The DVD format again requires... 4147200 Memory locations as required per frame by the 60hz/480 line NTSC standard. Both standards therefore only require just under 4 Megabits for a complete video frame. The ZERO in: 4:1:0 spec on R2/ 50hz / PAL DVD represents a further loss in colour detail. In conclusion. At the end of the day the final result is this. Both standards have identical HORIZONTAL resolution. The PAL standard has 20% greater VERTICAL resolution for fine brightness detail. BUT... This is at the LOSS of 50% of the colour fine detail !! Therefore on PAL / 576 line / 50hz 7/8th's of the total fine-colour-detail is lost from each frame. John Bingham Salford University " Written to site by Howard Simon Marks.